1. Field of the Invention
The present invention relates to a vacuum cleaner. In particular, the present invention relates to a cyclone dust collection apparatus, which is employed in a vacuum cleaner so as to filter dust suctioned from a surface together with air, using centrifugal force.
2. Description of the Related Art
In general, a vacuum cleaner comprises a bottom brush for suctioning dust from a surface together with air, a motor driving chamber provided with a driving source, and a vacuum cleaner body provided with a cyclone collection apparatus.
The cyclone collection apparatus is constructed in such a way that dust-entrained air, which is introduced from the bottom brush, is caused to form a swirling stream so that dust is separated from the air by centrifugal force, the dust is collected, and clean air is discharged into the motor driving chamber. In recent years, in order to improve dust collection efficiency, there has been proposed a cyclone dust collection apparatus that separates dust entrained in the air over two or more steps, wherein such a cyclone dust collection apparatus comprises one or more secondary cyclones.
The above-mentioned types of conventional cyclone dust collection apparatus are disclosed in WO02/067755 and WO02/067756 (Dyson Ltd). However, such conventional multi-clone dust collection apparatus has a disadvantage in that that because an upstream cyclone (a first cyclone), and a downstream cleaner (a second cyclone) are vertically arranged, thereby increasing the entire height of the dust-collection apparatus, they are mainly applied to an upright type cleaner but hard to be applied to a canister-type cleaner.
In order to solve the above problems, as disclosed in Korean Patent Application No. 2003-62520, it was possible to reduce the overall height of a cyclone dust collection apparatus by arranging second cyclones around the periphery of a first cyclone. However, efforts for reducing heights of dust collection apparatus have been continued so as to miniaturize cleaners. In addition, there was a need to reduce a flow path from an air outflow port, which is located above the top ends of the second cyclones of the dust collection apparatus, to a motor driving chamber, which is provided on the bottom of a cleaner so as to improve a pipe pressure loss.
Furthermore, in order to decrease the amount of dust that collects on a downstream part of the air flow path between the outlet of the first cyclone and the inlets of the second cyclones, where it is difficult for a user to clean, there is a need to increase the fine dust collection efficiency in the first cyclone.